Abu Bakr al-Baghdadi (name used for self-proclaimed caliph)

Abu Bakr al-Baghdadi was the leader of ISIS, a militant group that declared a caliphate in parts of Iraq and Syria around 2014. He claimed to be the spiritual and political leader of all Muslims worldwide, aiming to establish an Islamic state based on their extremist interpretation of Islam. Under his leadership, ISIS carried out brutal attacks, enforced strict laws, and gained international attention. He was known for his secretive nature and was eventually killed in a U.S. military operation in 2019. His leadership significantly influenced global security concerns related to terrorism.